Solar charge controller
Solar Controller Charger MPPT
loading controls come in all shapes, sizes, features and prices. They range from the small 4.5 amps command (Sunguard), up to 60 to 80 amp MPPT programmable controllers with computer interface. Often, if required current 60 amperes, two or more units 40 to 80 amplifiers are connected in parallel. The most common controls used for all battery-based systems fall within the range of 4-60 amps, but some of the new controls like the Outback MPPT power FlexMax go up to 80 amps.
loading controls come in three general types (with some overlap):
Simple controls 1 to 2 stages dependent bypass relays or transistors to control the voltage in one or two steps. These essentially just before or disconnect the solar panel when a certain voltage is reached. For all practical purposes, these are the dinosaurs, but there are some in old systems – and some of the super cheap for sale online. His only real claim to fame is its reliability – how have few components, there is not much to break.
3-stage and / or PWM such Morningstar, Xantrex, blue sky, Steca, and many others. These are more or less the industry standard, but occasionally still see some of the oldest types of bypass / relay all, and very cheap systems offering discount stores and mass merchandisers.
tracking the maximum power point (MPPT), such as those made by Midnite Solar, Xantrex, Outback food, Morningstar and others. These are the latest drivers, with prices to match – but with efficiencies in the range of 94% to 98%, you can save a lot of money in larger systems because they provide 10 to 30% more battery power. For more information, see our article on MPPT.
Most drivers come with some kind of indicator, either a single LED, a series of LED or digital meters. Many newer, such as inner power, classic Midnite, Morningstar MPPT, and others have built in computer interfaces command and control. The simplest usually have only a couple of small LED lamps, which show that you have the power and you are getting some kind of charge. Most of those meters display both voltage and current from the panels and the battery voltage. Some also show the amount of current is pulling the load terminals.
All charge controllers we stock are 3 types phase PWM and MPPT units. (Actually, “4 steps” is somewhat hype – what used to be called equalization, but someone decided it was better stage 4 to 3). And now we even see it advertised as “5 – stage” ….
For example, a car battery is flooded standard golf about 210 ampere-hours. So to keep them series (12 volts) to couple only maintenance or storage, you want a panel that is around 4.2 watts. The panels 5 watts popular are close enough, and will not need a controller. If you are maintaining AGM deep cycle batteries, such as the Concorde Sun Xtender then you can use a smaller panel of 2 to 2 watts.